/* ichika4.c - Don Yang (uguu.org)

   11/20/04
                                                                           */

#include<stdio.h>
#include<stdlib.h>


#define SHIFT_HUE       2.0f
#define SHIFT_SAT       0.70f
#define SHIFT_VAL       0.09f

#define EYE_HUE_MIN     3.60f
#define EYE_HUE_MAX     4.24f
#define EYE_SAT1        0.65f
#define EYE_VAL1        0.42f
#define EYE_SAT2        0.36f
#define EYE_VAL2        0.60f
#define EYE_THRESHOLD   0.6f
#define EYE_SCALE_VAL   1.29f

#define FACE_HUE1_MIN   0.30f
#define FACE_HUE1_MAX   0.45f
#define FACE_HUE2_MIN   4.28f
#define FACE_HUE2_MAX   6.00f
#define HAIR_HUE_MIN    0.0f
#define HAIR_HUE_MAX    0.1f

typedef float flt;

unsigned char *image, *mask, *m, *u, c;
int width, height, size, align, headersize, i, j, k;
flt r, g, b, h, s, v, r0, g0, b0, d1, d2, f, p, q, t;
char header[64], *errstr[] =
   {"read error", "write error", "invalid image", "out of memory"};

FILE *file;

void rgb2hsv()
{
   p = q = r;
   if( p > g ) p = g; if( q < g ) q = g;
   if( p > b ) p = b; if( q < b ) q = b;
   h = s = v = 0.0f;
   if( p != q )
   {
      p = q - p;
      h = (r == q) ? ((g - b) / p)
                   : (g == q) ? ((b - r) / p + 2.0f)
                              : ((r - g) / p + 4.0f);
      s = p / (v = q);
   }
}

int CheckNeighbors0(int offset)
{
   if( offset < width || offset > size - width ||
       !(offset % width) || !((offset + 1) % width) )
      return 1;
   r = (flt)*(image + offset * 3) / 255.0f;
   g = (flt)*(image + offset * 3 + 1) / 255.0f;
   b = (flt)*(image + offset * 3 + 2) / 255.0f;
   rgb2hsv();
   return
      ((FACE_HUE1_MIN < h && h < FACE_HUE1_MAX) ||
       (FACE_HUE2_MIN < h && h < FACE_HUE2_MAX) ||
       (HAIR_HUE_MIN < h && h < HAIR_HUE_MAX))
      ? 0 : CheckNeighbors0(offset + k);
}

int ErrorMsg()
{
   if( file ) fclose(file);
   return puts(errstr[k]);
}

void Erase(int offset)
{
   if( mask[offset] - 255 )
   {
      mask[offset] = 0xff;
      if( (offset % width) < width - 1 )  Erase(offset + 1);
      if( (offset / width) < height - 1 ) Erase(offset + width);
      if( offset % width )                Erase(offset - 1);
      if( offset / width )                Erase(offset - width);
   }
}

void ReorderBytes()
{
   u = image - 1;
   for(i = 0; i < size; i++)
   {
      c = *++u;
      *u = *(u + 2);
      *(u += 2) = c;
   }
}


int main(int argc, char **argv)
{
   if( argc < 3 )
      return printf("%s <infile.bmp|infile.ppm> <outfile>\n", *argv);

   k = width = 0;
   if( !(file = fopen(*++argv, "rb")) )
      return ErrorMsg();

   image = NULL;
   if( fread(header, 64, 1, file) - 1 )
      return ErrorMsg();
   k += 2;
   if( *header == 'B' && header[1] == 'M' )
   {
      if( *(int*)(header + 28) - 24 )
         return ErrorMsg();
      width = *(int*)(header + 18);
      height = *(int*)(header + 22);
      align = (4 - ((width * 3) & 3)) & 3;
      headersize = 54;
   }
   else if( *header == 'P' && header[1] == '6' )
   {
      for(i = j = headersize = 0; i < 63; i++)
         if( header[i] == '\n' )
            if( ++j == 3 )
            {
               header[headersize = ++i] = '\0';
               i = 64;
            }
      if( !headersize ||
          (sscanf(header, "P6\n%d %d\n", &width, &height) - 2) )
         return ErrorMsg();
      align = 0;
   }
   if( width < 16 || height < 16 )
      return ErrorMsg();

   k++;
   if( !(image = (unsigned char*)malloc((size = width * height) * 3)) )
      return ErrorMsg();
   u = image;
   for(fseek(file, headersize, i = 0); i < height; i++)
   {
      fread(u, width * 3, 1, file);
      u += width * 3;
      for(j = 0; j++ < align; fgetc(file));
   }
   fclose(file);
   file = NULL;

   if( *header == 'B' )
      ReorderBytes();

   if( !(m = mask = (unsigned char*)malloc(size)) )
      return ErrorMsg();
   u = image;
   for(j = 0; j < size; j++)
   {
      r = (flt)*(u++) / 255.0f;
      g = (flt)*(u++) / 255.0f;
      b = (flt)*(u++) / 255.0f;
      rgb2hsv();
      *m = 0xff;
      if( EYE_HUE_MIN < h && h < EYE_HUE_MAX )
      {
         d1 = (s-EYE_SAT1)*(s-EYE_SAT1)
            + (v-EYE_VAL1)*(v-EYE_VAL1) * EYE_SCALE_VAL;
         d2 = (s-EYE_SAT2)*(s-EYE_SAT2)
            + (v-EYE_VAL2)*(v-EYE_VAL2) * EYE_SCALE_VAL;
         if( d1 < EYE_THRESHOLD || d2 < EYE_THRESHOLD )
            *m = (unsigned char)(255.0f *
                    ((d1 < EYE_THRESHOLD) ? (d1 / EYE_THRESHOLD)
                                          : (d2 / EYE_THRESHOLD)));
      }
      m++;
   }

   for(i = j = k = 0; j < width;)
   {
      Erase(j);
      Erase(j + width);
      Erase(j + size - width * 2);
      Erase(j++ + size - width);
   }
   for(; k < height;)
   {
      Erase(k * width);
      Erase(k * width + 1);
      Erase((k + 1) * width - 2);
      Erase(++k * width - 1);
   }

   for(m = mask; i < size; i++)
   {
      if( *m - 255 )
         if( (CheckNeighbors0(i + (k = 1)) ? 1 :
              CheckNeighbors0(i + (k = -1)) ? 1 :
              CheckNeighbors0(i + (k = width)) ? 1 :
              CheckNeighbors0(i + (k = -width)) ? 1 : 0) )
            Erase(i);
      m++;
   }

   u = image;
   m = mask;
   for(i = 0; i < size; i++)
   {
      if( *m - 255 )
      {
         d1 = (flt)*m / 255.0f;
         d2 = 1.0f - d1;

         r = r0 = (flt)*u / 255.0f;
         g = g0 = (flt)*(u+1) / 255.0f;
         b = b0 = (flt)*(u+2) / 255.0f;
         rgb2hsv();
         if( (h += SHIFT_HUE) >= 6.0f )   h -= 6.0f;
         if( (s += SHIFT_SAT) > 1.0f )    s = 1.0f;
         if( (v += SHIFT_VAL) > 1.0f )    v = 1.0f;

         k = (int)h;
         f = h - (flt)k;
         p = v * (1.0f - s);
         q = v * (1.0f - s * f);
         t = v * (1.0f - s * (1.0f - f));
         r = (k < 4) ? (k < 2) ? k ? q : v
                               : p
                     : (k > 4) ? v : t;
         g = (k < 3) ? k ? v : t
                     : k > 3 ? p : q;
         b = (k < 3) ? (k > 1) ? t : p
                     : (k > 4) ? q : v;

         r = r0 * d1 + r * d2;
         g = r0 * d1 + g * d2;
         b = r0 * d1 + b * d2;
         *u = (unsigned char)(r * 255.0f);
         u[1] = (unsigned char)(g * 255.0f);
         u[2] = (unsigned char)(b * 255.0f);
      }
      u += 3;
      m++;
   }

   free(mask);

   if( *header == 'B' )
      ReorderBytes();

   k = 1;
   if( !(file = fopen(*++argv, "wb+")) )
      return ErrorMsg();
   fwrite(header, headersize, 1, file);
   u = image;
   for(j = 0; j < height; j++)
   {
      fwrite(u, width * 3, 1, file);
      for(k = 0; k < align; k++)
         fputc(0, file);
      u += width * 3;
   }
   fclose(file);

   free(image);
   return 0;
}